1. Field of the Invention
The present invention relates to an apparatus for hinging together the housings of foldable devices, and particularly to an apparatus for hinging together the housings of a foldable mobile phone.
2. Description of Related Art
Portable radiotelephones having two housings joined by a type of hinge that allows the housings to fold upon one another are known in the art. Some such folding radiotelephones have most of the electronics in one housing, called the main housing, and fewer electronics in the other housing, called the cover. Other such folding radiotelephones have all the electronics in the body with the cover serving only to cover the keypad or keypad and display of the phone. Manufacturers have tried to reduce the volume, size and weight of the portable radiotelephone. Thus, it is desirable that the hinge coupling the main housing with the cover is modulated and miniaturized. The modulated hinge device is required to have the structure for holding moving parts of the hinge, such as a cam member, a cam follower and a spring. For miniaturization, the size and the number of parts of the hinge should be reduced.
Such a hinge assembly is disclosed in U.S. Pat. No. 5,628,089, as shown in FIG. 5, which includes a can 303 for encasing a spring 405, a cam 404, and a cam follower 403 therein. A cap 305 covers the can 303 at an opened end thereof. The cam follower 403 is engaged with the cam 404 with a tab 415 of the cam follower 403 moving along a cam surface 419 for being received in valleys of the cam 404. The cam 404 can slide in the can 303 by way of rails 417 on an exterior surface 467 of the cam 404 sliding in guides 437 in an interior surface 465 of the can 303. The cap 305 covers over the can 303 with two arms 409 being inserted into slots 423 defined in an exterior surface of the can 303 and two barbs 411 being latched into holes 435, while a head 413 of the cam follower 403 extends through a hole of the cap 305 and a step 445 is fitted in the hole of the cap 305, thus the cam components are assembled and fixed into the can 303. However, the cam follower 403 has a very complicated configuration for manufacturing. Furthermore, the locking means by way of two barbs 411 being latched into holes 435 is not reliable, and it can be easily dismissed during cover rotation of the folding phone.
Therefore, an improved hinge assembly is desired which overcomes the disadvantages of the prior art.